An interesting but ultimately flawed point of view.
Pentax come up with the Q, and the K-01... when the choice of making a proper mirrorless camera system wasn't an option. Both were developed while Hoya was preparing to sell them to Ricoh.
The old full frame project was canceled because of the sensor, and the other camera using the same sensor (Contax) failed miserably.
Pentax has more FF K-mount lenses than the Sony FE.
Last but not least, going mirrorless - what you seems to think it's the "right" kind of camera - wouldn't solve any one of those points. On the contrary, on the lens side things would've been much more dire.
The old FF "project" was not canceled due to the sensor. Contax was the 1st one to come with a FF sensor DSLR, actually, announced in 2000 and came to market in 2002 using a Philips 6mp sensor. The really old Pentax FF project which was based on the same sensor was canceled on 2001. That was even before Canon came with its 1st FF sensor DSLR.
But Pentax has been showing FF mock up "prototypes" all through the FF DSLR height (or hype?) last 1.5 decade. So, a bit odd to only mention their very first flirtations with FF.
Sony now has some very impressive lenses (counting Zeiss, and other 3rd party offerings), just no good body. All hampered with bad ergonomics, tiny badly layed out controls, poor battery life and bad RAW format.
So, now you have the choice of a impressively specced Pentax K1 for everything except fast tracking photography, with a lens line up which leaves some to be desired, and on the Sony side a plethora of small and not too attractive to use FF bodies with some very impressive lenses.
And then you have Nikon and Canon with their much bigger following, with mostly well thought out DSLR bodies and pretty full range of lenses.
Indeed, going mirrorless will not solve anything. You probably will end up with yet another small, not so ergonomic camera, with bad battery life, all the downsides that come with EVF, and no lens line up.
I do hope that the K1 will find buyers in big enough numbers.